84 results about "Phase diversity" patented technology

Systems, including apparatus and methods, for obtaining and/or correcting images, particularly from atmospheric and/or other distortions. These corrections may involve, among others, determining corrective information in a first (e.g., visible) wavelength regime, and then applying the corrective information in a second (e.g., longer) wavelength regime, such as infrared (IR) or millimeter-wave (MMW) wavelengths, in real time or with post-processing. For example, these corrections may include scaling a phase diversity correction from one wavelength to another. These systems may be useful in any suitable imaging context, including navigation, targeting, search and rescue, law enforcement, and/or surveillance, among others.

The invention relates to an off-focus value measuring method for a phase diversity wavefront sensor. By ensuring directional light to enter the phase diversity wavefront sensor (PD WFS), a processing algorithm utilizes an off-focus plane far-field light spot image to restrain the solving process on the basis of the conventional GS iterative operation according to the orthogonality that the off-focus plane only comprises an off-focus phase diversity and a Zernike polynomial, so that the accurate measurement of the off-focus value of a system is implemented. Relative to various current off-focus measuring methods for the PD WFS, the off-focus value measuring method for the PD WFS, which is disclosed by the invention, has the advantages that the structure is simple and stable; the solving process is rapid and reliable; the position of a photoelectric detector CCD (Charge Coupled Device) does not need to be moved in an optical path; other measuring tools are not used; in the iterative process, various prior information is sufficiently utilized to increase the constraint conditions, so that the defect that in a conventional GS algorithm, a correct result cannot be accurately obtained due to the insufficient constraint conditions is overcome; the off-focus value measuring method has higher off-focus value measuring accuracy and stability; and the foundation is laid for the PD WFS toaccurately measure the wavefront phase diversity and recover a degrade image in the actual engineering.

A geometric measurement system is adapted to precisely measure one or more surfaces of objects such as corneas, molds, contact lenses in molds, contact lenses, or other objects in a fixture. The geometric measurement system can employ one or more of three possible methods of measurement: Shack-Hartmann wavefront sensing with wavefront stitching; phase diversity sensing; and white light interferometry.

The present invention relates to an omnidirectional base station antenna arrangement with a number of antenna elements and a number of transceiver means for transmitting and receiving signals to/from a number of user stations. A feeding network is provided which comprises a number of phase ports, a number of which form first phase ports connected to a number of transceiver means for downlink communication and a number of which form second phase ports connected to a number of transceiver means for uplink communication. The feeding network comprises a number of antenna ports connected to antenna elements and the feeding network generates substantially independent, orthogonal signals to provide for phase diversity and the antenna elements are arranged to form at least one cylindrical array antenna. The invention also relates to a method of providing communication between an omnidirectional base station antenna arrangement with a number of antenna elements and a number of transceiver means and a number of user stations as well as to a method of providing for at least phase diversity transmission at an omnidirectional base station antenna arrangement.

The invention relates to a method for detecting the surface shape of a large-aperture telescope by using phase diversity phase retrieval. The method comprises the following steps of: representing a 2-bit variable by using a 1-bit variable in order to representing an imaging relation of an optical system; expanding a wave aberration into a series, solving a transfer function by using self-correlation operation of a pupil function and changing a Zernike coefficient so as to obtain different transfer function calculating results, comparing the transfer function calculating results with a transfer function result acquired from the Fourier transform of a measured point spread function, using a minimum mean square error result as a solution; and solving an evaluation value E. The method for detecting the surface shape of a spherical mirror on the basis of phase diversity phase retrieval in a focal plane detector is low in development cost, simple in hardware, susceptible of influences of environment (especially vibration), and capable of dynamically detecting optical elements and systems.

In one embodiment, a method for performing antenna diversity combining for digitally broadcast radio signals includes generating a first signal quality metric for a first signal obtained from an incoming digitally broadcast radio signal received in a first signal path, and similarly generating a second signal quality metric for a second signal obtained from the radio signal received in a second signal path. Then the first and second signals from these paths can be coherently combined based on the signal quality metrics to obtain a combined frequency domain symbol. In some embodiments, this combined frequency domain symbol may be remodulated to a time domain symbol. Also in some embodiments N tuners can be daisy chained to generate a final output that is either a frequency domain symbol of combined sub-carriers, soft bits to a forward error correction (FEC) decoder, or a remodulated time domain symbol. As a further possibility, each of the N tuners can use a different local oscillator (LO) frequency.

The invention discloses a self-adaptation optical system near-field wave-front sensor calibration device and a calibration method based on a phase-diversity method. The self-adaptation optical system near-field wave-front sensor calibration device consists of a wave-front corrector, a spectroscope, a near-field wave-front sensor, a wave-front controller, an imaging system and a phase-diversity wave-front sensor. According to the method, the phase-diversity wave-front sensor is used for measuring the static aberration of the whole system, and the wave-front controller is used for controlling the wave-front corrector to correct the static aberration; and after the static aberration is corrected, the zero point at the reference position of the near-field wave-front sensor at the pupil plane position is calibrated or the zero point of the absolute aberration is set, and the two zero points are used as the wave-front control objective of the self-adaptation optical system to effectively correct the static aberration of the whole optical path. According to the self-adaptation optical system near-field wave-front sensor calibration device and the calibration method, the static aberration of the whole optical path can be effectively corrected, the wave-front control error caused by the non-linear response of the corrector can be avoided, and the correction capability of the self-adaptation optical system can be improved obviously without obviously increasing the system complexity and the additional aberration.

The present invention discloses a method and an apparatus for measuring quality parameters of optical transmission channels. The apparatus comprises: a tunable optical filter for receiving an optical signal, performing wavelength or optical carrier demultiplexing on the optical signal, and out-of-band ASE noise suppression; an optical coherent receiver connected to the tunable optical filter, for performing polarization- and phase-diversity detection on the filtered optical signal and converting it into multiple lane baseband electrical signals; analog-to-digital converters for sampling and quantizing the multiple lane baseband electrical signals so as to convert the them into multiple lane digital signals; a digital signal processing module for processing the multiple lane digital signals to obtain quality parameters; and an display module for displaying the quality parameters. By the device according to an embodiment of the invention, real-time measurement of various key performance parameters of the 40 Gbps, 100 Gbps and extra-100 Gbps (for example, 200 Gbps, 400 Gbps and 1 Tbps) coherent polarization-multiplexed system is achieved simultaneously, especially the issue of real-time measurement of the in-service in-band OSNR is solved. Therefore, the network operation and maintenance are facilitated and the cost of network operation and maintenance is saved.

A geometric measurement system is adapted to precisely measure one or more surfaces of objects such as corneas, molds, contact lenses in molds, contact lenses, or other objects in a fixture. The geometric measurement system can employ one or more of three possible methods of measurement: Shack-Hartmann wavefront sensing with wavefront stitching; phase diversity sensing; and white light interferometry.

A method for reducing a piston between a plurality of optical-collection devices configured to operate as a single optical device, such that the optical-collection devices are configured to capture select portions of a wavefront. The method includes pistoning an adjustable-optical path of at least one of the optical-collection devices through a plurality of steps; collecting a set of focused images and a set of defocused images for each step; Fourier transforming the first and second sets of images to generate respective first and second sets of spectral information for the wavefronts; deriving a set of wavefront errors based on the first and second sets of spectral information using a phase diversity algorithm; and deriving a piston value for the piston from the wavefront errors using a multi-color interferometry algorithm.

The invention discloses a phase diversity wave front measurement imaging device based on difference optics, which comprises a light beam matching system, an imaging lens, a spectroscope, a reflecting mirror, a reflecting mirror with small holes, a translation mechanism and a photoelectric detector CCD (charge-coupled device). The phase diversity wave front imaging device is characterized that a difference optics system can simultaneously obtain a focal plane image and an out-of focal plane image of the same target by a photoelectric detector; the light intensity energy of a target to be imaged can not be lost; an out-of focal plane can obtain continuous adjustable out-of focusing amount which increases from zero gradually; and the positions of the focal plane image and the out-of focal plane image in a target surface of the photoelectric detector CCD can be adjusted randomly. Compared with the various imaging technologies used in phase diversity, the phase diversity wave front measurement imaging device is simple and stable in structure, can simultaneously obtain the focal plane image and the out-of focal plane image by the photoelectric detector, can flexibly adjust various parameters used for the phase diversity, can realize maximum light energy utilization, and establish a foundation for a phase diversity wave front measurement technology in actual engineering, particularly an application of the phase diversity wave front measurement technology under a weak light condition.

A system to determine the distance to an object includes one or more aberrating elements to introduce aberration into light from the object. Image data is obtained at two different focus conditions, and used to determine the object distance.

The invention discloses a human eye aberration measuring system based on phase diversity, which comprises an optical illuminating system, a pupil aligning system, an optical staring system and an optical imaging system. The optical illuminating system is mainly an optical system which illuminates the fundus oculi of a human eye by the aid of infrared during detection, the pupil aligning system is a system for aligning the human eye with an optical axis of the optical illuminating system and an optical axis of the optical imaging system before detection, the optical staring system is mainly an optical system for fixing the position of the eyeball of the human eye during detection, and the optical imaging system is mainly a system for realizing observation imaging for the area of the fundus oculi illuminated by the illuminating system. The human eye aberration measuring system overcomes shortcomings that in the prior art, objective aberration measurement time is long, individual aberration correction cannot be guided, measurement accuracy is low, a measurement range is small and the like.

An optical measuring apparatus, includes an optical branch element for splitting a measured light into plural lights, a time delay processing portion for giving a predetermined time delay to one split light of the measured light, an optical phase diversity circuit for outputting an in-phase signal component and an quadrature-phase signal component of the measured light by virtue of an interference between the measured light and a reference light between which a relative time difference corresponds to a time give by the time delay, while using other split light of the measured light or the measured light to which a process is applied by the time delay processing portion as the reference light, a data processing circuit for calculating at least one of an amount of change of an amplitude and an amount of change of a phase of the measured light, based on the in-phase signal component and the quadrature-phase signal component, and an optical time gate processing portion or an electric time gate processing portion provided on a route extending from the optical branch element to the data processing circuit, for extracting at least one of split lights of the measured light every predetermined bit time while shifting a timing, wherein changes of amplitude/phase distributions in time are measured.

A system capable of determining wavefront characteristics, such as air induced wavefront aberrations, includes a field programmable gate array (FPGA) device executing a phase diversity algorithm. The FPGA device can be a stand-alone device or comprise multiple FPGAs. The device receives an “in-focus” and an “out-of-focus” image having a known optical difference from that of the “in-focus” image. The device then performs as many phase diversity algorithm iterations as desired to reach an expression for the wavefront aberrations induced on the collected image data. The resulting wavefront data may be used to produce an enhanced image of the original image data. Example applications include remote sensors and targeting systems, and both passive imaging and active projection systems that compensate for wavefront anomalies.

A diversity receiver includes first and second reception circuits using a superheterodyne principle. At stationary reception, reception of the audio signals and the data employing a phase diversity reception system is performed such that the signals received by the first reception antenna are supplied to the first reception circuit, the signals received by the second reception antenna are supplied to the second reception circuit, and phases of first and second intermediate-frequency signals are controlled and the first and second intermediate-frequency signals are added. At reception-frequency search, reception of the audio signals employing an antenna-switching diversity reception system is performed such that the signals received by at least one of the first and second antennas are supplied to the first reception circuit and reception of the data and the reception-frequency search are performed, and the signals received by the first and second antennas are supplied to the second reception circuit.

The invention relates to an optical mixer for reflective coherent receives, belongs to optical devices of optical fiber communication and solves the problem that existing optical mixers are non-compact in structure and poor in temperature stability. A polarization separator, a 1/2 wave plate, a phase shift plate, a first shift crystal, a 1/4 wave plate and a combined reflecting mirror are sequentially arranged along an incident light path, and the 1/4 wave plate, the first shift crystal, the 1/2 wave plate and a second shift crystal are sequentially arranged on a reflecting light path of the combined reflecting mirror, wherein the 1/2 wave plate, the first shift crystal and the 1/4 wave plate are shared devices. Polarization separating is realized through a polarization separation prism, 90-degree phase shift is realized through the phase shift plate, safe-phase and orthogonal output light required is obtained by adopting the reflecting structure, birefringent crystals, the 1/4 wave plate, the 1/2 wave plate and the combined reflecting mirror, and polarization and phase diversity control is realized. The optical mixer is compact in integral structure, mature in processing technique of various devices, good in temperature stability and high in polarization extinction ratio, and can be used for optical signal coherent modulation by advanced modulation formats and polarization multiplexing way in the optical fiber communication.

Disclosed is a light measurement apparatus including: an optical branching device to branch light to be measured into a plurality of pieces; a time delay processing unit to give a predetermined time delay to one branched piece of the light; an optical phase diversity circuit to output an in-phase signal component and a quadrature-phase signal component of the light to be measured by interference of the light to be measured and a reference standard light whose relative time difference is a time given by the time delay, wherein the reference standard light is another branched piece of the light or the one branched piece of the light having been subjected the time delay; and a data processing circuit to calculate at least one of an amplitude variation and a phase variation of the light to be measured based on the in-phase signal component and the quadrature-phase signal component.

The invention discloses a system for adopting a phase diversity receiving technology to receive coherent light orthogonal frequency division multiplexing access signals. The system comprises a phase modulator, an erbium-doped optical fiber amplifier, an optical phase diversity receiver, a first photoelectric detector, a second photoelectric detector and a phase estimation module. The OOFDM signals after standard single mode optical fiber long-distance transmission are processed by the optical phase diversity receiver and the phase estimation module respectively, therefore, the negative effects of optical fiber dispersion and polarization mode dispersion can be effectively resisted, and the receiving quality of the OOFDM signals after long-distance transmission is improved.

A clear image of a target to be measured is obtained by suppressing influence of a reflected beam from the surface of the target or a measurement target holding unit. A laser beam emitted from a light source is split into a signal beam, reference beam, and control beam. The signal beam is focused onto the target with an objective lens, so the target is irradiated with the signal beam. The amount of defocus of the control beam is controlled with a defocus control unit, and the phase of the control beam is controlled with a phase control unit. A signal beam reflected or scattered by the target is combined with the control beam to generate a controlled signal beam, and the controlled signal beam is combined with the reference beam. A plurality of interference beams with different phases are generated with interference optics, and phase diversity detection is performed.